Di2 Battery Holder for 25.4 mm Seat Posts


This battery holder is for Shimano Di2 internal SM-BTR2 and BT-DN110 batteries. The battery fits inside the seat post and typically requires a seat post made specifically for Di2. This holder allows the battery to be held securely within a non-Di2 specific 25.4mm seat post found on many bikes from 2014 to present. It will also fit other seat posts with the same inside diameter.
Weight: 6-7g

Made from a flexible plastic material.  Fits very tightly.

Collections: Di2-eTAP Conversion Accessories

Battery Holder Sizes

We make Di2 battery holders for 25.4mm seat posts with various inside diameter size options.  If you are using a seatpost not listed here, please contact us for assistance.

Cannondale® Branded

C2 - 19 mm ID (Carbon)

C3 - 19.5 mm ID (Aluminum)

SAVE - (uncut - tapered) (BETA limited testing)

Focus® Branded

BBB Basic - 19.65 mm ID (Aluminum)

FSA® Branded

SLK Carbon - 20.5 mm ID (Carbon)

Zipp® Branded

Zipp Service Course SL Carbon - 22 mm mm ID (Carbon)


Why use a holder instead of tape or foam?

Ad hoc solutions using tape and foam have multiple issues. The net result is often a damaged or stuck battery.

Problems with Tape or Foam:

  • They don't protect the delicate battery connection
  • Tape or foam can shrink, causing the battery to fall out
  • They can cause the battery to overheat
  • Tape, especially, can fuse to the inside of the seat post




How to Remove the Poly Holder

Removing the holder requires pliers.  Never use pliers on the battery itself.

  1. Grip the flat surface of the holder with pliers.
  2. While holding the pliers steady, rotate the seat post while gently pulling it away from the pliers.
  3. When the holder is about 1/2" (10-15mm) extracted, release the pliers.
  4. The holder and battery can now be removed by hand.



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COVID-19 Impact

COVID-19 is impacting us all. By now you have received notifications from everyone related to this serious crisis. Bup Labs is still open for business, but we are also providing help to various entities related to COVID-19 care. As a result of the additional efforts and the lack of some supplies used in our manufacturing processes, our production has slowed. We have taken extra precautions to ensure environmental safety is adhered to for both incoming and outgoing products and materials. We appologize for the delays and ask for your patience during this trying time.